Peter O. D. Pharoah

NEUROLOGICAL DAMAGE TO THE FETUS RESULTING FROM SEVERE IODINE DEFICIENCY DURING PREGNANCY

Summary Endemic cretinism is characterised by multiple neurological defects including deaf-mutism, diplegia, squint, and mental deficiency. The condition is widely prevalent in the Highlands of New Guinea in association with severe iodine deficiency. Previous studies have shown that iodised oil provides a very satisfactory correction of severe iodine deficiency in New Guinea. A controlled trial on the use of intramuscular iodised oil in the prevention of endemic cretinism was carried out in the Western Highlands of New Guinea and involved a population of approximately 8000. Subsequent follow-up over four years revealed 26 endemic cretins out of a total of 534 children born to mothers who had not received iodised oil; the mothers of 5 of these cretins were pregnant at the start of the trial. In comparison, 7 cases of endemic cretinism occurred among 498 children born to mothers who had been treated with iodised oil; in 6 of these 7 cases, the mother was pregnant when the trial commenced. It is concluded that intramuscular iodised oil is effective in the prevention of endemic cretinism and that, for it to be effective, it should be given prior to conception. This suggests that severe iodine deficiency in the mother produces neurological damage during fetal development.

Birthweight specific trends in cerebral palsy.

A register of infants with cerebral palsy born to mothers resident in the Mersey region from 1967-84 has been maintained using various sources of information. A total of 1056 patients are registered of whom 331 (31%) have hemiplegia or mixed hemiplegia, 236 (22%) have diplegias or mixed diplegia, and 369 (35%) have quadriplegia or mixed quadriplegia. The remainder have dyskinetic or dystonic forms except for seven, who are unclassified. There has been no significant change in the prevalence of cerebral palsy among infants of normal birth weight (greater than 2500 g). Among low birthweight infants (less than or equal to 2500 g) there has been a significant increase in prevalence of all the main clinical types. This increase started later among the very low birthweight infants (less than or equal to 1500 g) than among those weighing 1501-2500 g. These changes in prevalence could be the result of either improved survival of prenatally impaired infants because of improvements in medical care, or a reflection of failure to maintain optimal conditions at or around the time of birth.

Life expectancy in children with cerebral palsy.

Abstract Objective : To determine life expectancy of children with cerebral palsy. Design : Cohort analysis, by means of register compiled from multiple sources of ascertainment, of all children with cerebral palsy born during 1966-84 to mothers resident in Mersey region. Status of children was determined by flagging through NHS central register. Subjects : 1258 subjects with idiopathic cerebral palsy, of whom 1251 were traced and included in analysis. Main outcome measures : Effect of functional ability (ambulation, manual dexterity, and mental ability), sex, birth weight, and gestational age on survival. Results : 20 year survival for whole cohort was 89.3% for females and 86.9% for males. For subjects with no severe functional disabilities 20 year survival was 99% (95% confidence interval 98% to 100%), while subjects severely disabled in all three functional groups had 20 year survival of 50% (42% to 58%). Subjects with birth weight <=2500 g had 20 year survival of 92% (89% to 95%), while those with birth weight <2500 g had survival of 87% (84% to 89%). Subjects with gestational age of <37 weeks had 20 year survival of 93% (91% to 96%), while those with gestational age >=37 weeks had survival of 85% (83% to 88%). Birth weight and gestational age were less predictive of survival than functional disability. Best statistical model used gestational age and number of severe functional disabilities as predictors. Conclusions : Life expectancy of this cohort of children with cerebral palsy was greater than has been suggested in some previous studies. This has important implications for social, educational, and health services.

Cerebral palsy -the transition from youth to adulthood

Service provision for those with cerebral palsy (CP) becomes fragmented after adolescence. Young people with CP in two age groups, their carers and associates, were interviewed, and use of health and social services was investigated. Leisure activities were also compared with a matched control group of able‐bodied young people. Use of health and social services decreased when the children with CP left school, thereby increasing the demands upon carers. Carers expressed anxieties about the provision of services, and frustration in obtaining information about help. Findings from the questionnaires showed the young people with CP in both age groups to be socially less active than the controls. Among the subjects, the older age group was socially less active than the younger age group. Communication is poor both between the agencies providing care and between the agencies and the young person or carer. There is a need to identify those with responsibility for coordinated‐care planning for adolescents with CP.

Differential effects of preterm birth and small gestational age on cognitive and motor development

AIMS To determine the differential effects of preterm birth and being small for gestational age on the cognitive and motor ability of the child. METHODS A longitudinal cohort of all infants of gestational age ≤ 32 weeks born to mothers resident in the counties of Cheshire and Merseyside in 1980-1 was studied. The children were assessed at the age of 8 to 9 years using the Wechsler Intelligence Scale for Children, the Neale analysis of reading ability, and the Stott-Moyes-Henderson test of motor impairment. Adequacy of fetal growth was determined by the birthweight ratio—that is, the ratio of the observed birthweight to the expected birthweight for a given gestational age. Children with clinically diagnosed motor, learning or sensory disabilities were excluded. Information on social variables was obtained by a questionnaire completed by the parents. Of the 182 children, 158 were assessed. RESULTS IQ was positively correlated with birthweight ratio but not with birthweight or gestational age. Motor ability was associated with birthweight, gestational age, and birthweight ratio. Reading comprehension was associated with birthweight ratio, but reading rate and accuracy were best explained by social variables and sex. IQ remained associated with birthweight ratio, after adjusting for maternal education, housing status, and number of social service benefits received. Reading ability was related to these social variables but motor ability was not. CONCLUSIONS The effects of SGA and preterm birth differed: SGA was associated with cognitive ability, as measured by IQ and reading comprehension; motor ability was additionally associated with preterm birth. Reading rate and accuracy were not associated with SGA or preterm birth but were socially determined. Key points Preterm birth and being small for gestational age differ in their effects on motor and cognitive development Cognitive ability, as measured by IQ and reading comprehension, was negatively associated with the degree of fetal growth retardation Motor ability was positively associated with gestational age and negatively associated with the degree of fetal growth retardation Reading rate and reading accuracy were not associated with either gestational age or the degree of fetal growth retardation, but were socially determined

The changing epidemiology of cerebral palsy.

AIM: To determine the prevalence of cerebral palsy in a specific population. METHODS: Multiple sources of ascertainment were used to create and maintain a register of all cases of cerebral palsy born to mothers resident in the counties of Merseyside and Cheshire in the years 1966 to 1989. Denominator data of infant births and deaths from 1966 to 1981 were obtained from statutory notifications made to health authorities and, for the period 1982-89, from statutory birth and death registrations. Over 1500 cases formed the database for the study. RESULTS: The prevalence of cerebral palsy has increased among all the low birthweight groups with, most recently, an increase in infants weighing < 1000 g at birth. Low birthweight infants now comprise about 50% of all cases of cerebral palsy; in the early years of the study they comprised about 32% of all cases. The proportion of cerebral palsy by clinical type has changed among low birthweight babies, with relatively fewer cases with diplegia and a concomitant increase in the proportion with hemiplegia. An increase in the severity of functional disability, determined by the proportion of children with severe learning, manual, and ambulatory disabilities, was also found. CONCLUSIONS: The change in the epidemiology of cerebral palsy has implications for the aetiology of the condition, and for health, educational, and social service provision.

Prevalence of behaviour disorders in low birthweight infants.

OBJECTIVE--To determine the prevalence of behaviour disorders in low birthweight infants. DESIGN--Children of birth weight < or = 2000 g born to mothers resident in Merseyside in 1980-1 assessed using the Rutter parent and teacher behaviour questionnaires and the Conner modification of the Rutter teacher questionnaire. Children attending normal schools were assessed with controls matched for age, sex, and class in school. Children attending special schools were assessed unmatched. SUBJECTS--233 matched case-control pairs attending normal primary schools and 46 unmatched children attending special schools. SETTING--Primary and special schools. MAIN OUTCOME MEASURES--Emotional, conduct, and undifferentiated behaviour disorders and hyperactivity. RESULTS--On the parental questionnaire screen, 36% of the cases and 22% of the controls had a behaviour disorder and on the teacher questionnaire the proportions were 27% and 12% respectively. Hyperactivity was significantly more common among male cases than their controls (21% v 5.0%) but differed little among female cases and controls (9% v 7%). CONCLUSIONS--Improving neonatal survival of low birthweight infants is accompanied by a higher prevalence of behaviour disorders. The long term implications for psychiatric morbidity and other adult disease must be monitored.

Lung function and respiratory health in adolescents of very low birth weight

Aims: To determine if very low birth weight (VLBW; birth weight <1500 g) is associated with reduced lung function and respiratory health in adolescence and, if it is, whether this impairment is associated with prematurity or intrauterine growth restriction. Methods: A geographically defined cohort of 128 VLBW infants and an age, sex, and school matched comparison group born in 1980/81 were studied. The cohort and comparison group were assessed at 15 years of age. The birth weight ratio of the index cases (observed birth weight/expected birth weight for the gestation) was determined to assess the degree of growth restriction. Respiratory support received during the neonatal period was obtained from hospital records. Smoking habits and respiratory morbidity were obtained through questionnaires. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and forced expiratory flow when 25–75% of FVC is expired (FEF25–75%) were measured using a portable spirometer. The values are expressed as percentage predicted for height, age, and gender using standard reference values. Adjustments were made for smoking habits of mother and children. Results: The differences in means between index and comparison groups for FEF25–75% (−12.42%; p < 0.001) and FEV1/FVC (−3.53%; p < 0.001) ratio were statistically significant. The differences in FVC and FEV1 were not significant. No correlation was found between the birth weight ratio and lung function among the index cohort. Chronic cough, wheezing, and asthma were more common among the index cohort than in the comparison group. Within the index group, there was no difference in lung function between those who received and those who did not receive respiratory support. Conclusion: Adolescents who were VLBW compared with matched controls showed medium and small airways obstruction. This was associated with prematurity rather than intrauterine growth restriction or having received respiratory support during the neonatal period. The index VLBW cohort compared with their controls were also more prone to chronic cough, wheezing, and asthma.

Trends in birth prevalence of cerebral palsy.

A register of children with cerebral palsy born in the period 1966-77 to mothers resident in the Mersey region was compiled from several different data sources. There were 685 cases, with a male:female ratio of 1.4:1. The birth prevalence of cerebral palsy ranged from 1.18 to 1.97 per 1000 live births each year, with a mean of 1.51 per 1000 live births. There was no discernible trend in overall prevalence, but there was a highly significant upward trend in the prevalence of cerebral palsy among low birthweight infants, which was evident for all the major types of cerebral palsy. It is postulated that this is due to improved survival rather than a real change in incidence. Alternatively, because the register was compiled from health service records, a diagnostic access bias from improved follow up of low birthweight infants may have led to an apparent increase in prevalence.

Long‐term survival for a cohort of adults with cerebral palsy

The aim of this study was to investigate long‐term survival and examine causes of death in adult patients with cerebral palsy (CP). A 1940–1950 birth cohort based on paediatric case referral allows for long‐term survival follow‐up. Survival is analyzed by birth characteristics and severity of disability from age 20 years (and age 2y for a subset of the data). Survival outcome compared with that expected in the general population based on English life tables. The main cohort consisted of 341 individuals, with 193 males and 148 females. Conditional on surviving to age 20 years, almost 85% of the cohort survived to age 50 years (a comparable estimate for the general population is 96%). Very few deaths were attributed to CP for those people dying over 20 years of age. Females survived better than males. However, females faced a greater increase in risk relative to the general population than did males. We conclude that survival outlook is good though lower than in the general population. The relative risk of death compared with the UK population decreases with age, although it shows some indication of rising again after age 50 years. Many more deaths were caused by diseases of the respiratory system among those dying in their 20s and 30s than would be expected in the general population. Many fewer deaths than expected in this age group are caused by injuries and accidents. For those people who die in their 40s and 50s, an increase in deaths due to diseases of the circulatory system and neoplasms is observed. More deaths than expected in this age group are due to diseases of the nervous system.